Glass fiber spring unit and method of making same



Sept. 30, 1958 w. E. 'JONES ETAL GLASS FIBER SPRING UNIT AND METHOD OF MAKING SAME GYGLES T0 50% GOMPRESS'ON FIG-6 2 M, .ma

Original Filed March 13. 1952 LECEEEEEEEE UDUDUUUDUDD UDUUDUUDDDUW UDUUUUUDUUUH UUUUUDUUUUUW UUUUUUUUUDUH UDUDUUUDUUUW UUUUUUUUUGUW UUUDUUUUUUUH UUDDDUUUDUUW UDDUUUDDEUUW UNVENTORS.

^ WBLUAM &JONES FRANK A. MAROVlCH BY #W ATTORNEYS United States Patent* O GLASS F IBER SPRING UNIT AND METHOD MAKING SAME William E. `Tones, Reseda, and Frank-A. Marovich, Los Angeles, Calit., assignorszto Vibradamp Corporation; Toledo, Ohio, a corporation of California continuation of application Serial No. 276,308, March 13, 1952. This application October 31; 1955,* Serial No. 543,814

17 Claims. (CL .267`--1) This invention relatesoto cushioning devices or. spring units, for example, such as seat cushions, mattressesand other cushioning structures adapted to preferably have individual springing support throughontthe, area ofjthe cushion. V

This application isa continuation of application, Serial No. 276,308, filed March 13, 1952, now abandoned.

It is common in the art of cushioning devices to use sponge rubber or foam rubber or metal springs to secure cushioning effect in seat cushions,` mattresses and the like. However, ithas not heretofore been consideredthat. glass fibers could be adapted for use in the manufacture, of such articles as seat cushions and mattresses.

However, in the co-pending application of Joachim Bush, Serial Number 268,049, filed January 24, 1 952, now U.,S. Patent No. 2,600,843, of common assignee with this application, thereis disclosed a glass fiber shock absorbing or spring material and a, process for producing the same that adapts the glass fiber material for ree silient springing suspensions.

It is, therefore, an object of this invention to provide a glass fiber spring unit or cushion constructed in a manner to obtain the effects of the action of a plurality of`indiyidual springs cooperating to resiliently support an object, and a method of producing such a springunit or cushion.

It isanother object of the invention to'produce a spring unit or cushion from a body of glass fibers bonded togetherin a manner for resilient compression of the body, the body of glass fibers being of uniform density with the glass fiber body being fabricated in a manner to provide a plurality of independently acting resih'ent spring bodies of glass fibers Whereby the spring unit or cushion Will support objects of'irregular shape in the manner of a. mattress or acushion,

Further objects and advantages will become appa cnt from the drawings and the following description.

Inthe drawings:

Figure 1 is a side elevational view ofa body cushion constructed in accordance with this invention.

Figure 2` is an elevational view of the body cushion of Figure 1 as viewed from the top side thereofr i l l 1 1 s trating the independent resilient spring elements,

Figure 3 is an end elevational view of the body cushionof Figure 2.

Figure 4 is an enlarged perspective View of onecorner of the body cushion.

Figure 5 is a chart illustrating the stabilization curve of the glass fibrous material used in the body cushion Figure 6 is a load deflection curve of the stabilized glassfibrous material used in the body cushion.

Figure 7` is a View of a modified positioning of; the cushion.

The glass fiber body cushion ofithis invention is constructed of a glass fiber material like that disclosedin the co-pending application of Joachim Bush, Serial Number 268,049, filed' January 24, 1952, now U. S. Patent No. 2,600,343, and may be produced according to the As disclosed in the aforementioned' application, the

shock absorption or spring material iscomposedpfjglass fiber-s that may be produced in any one of several well& known deyicesby which the glass fibers are collectedas a felted assemblage in the form of a mat or apad; These glass. fibers may be long continuous length fibers, or hey an shor eng h. stap efib s, r mixtur t hem., Bretet b m h g ass fibers, used*` n he, sh el; a sorption r. spri g m t r a r those., ha ng i: ameter. oi b tween 0.011005 and 000025 inch,, commonly assified s.. B3 fiber. nth gl ss fib r indus ry..

Dnrin l he-cpn seo ma n a ur ofu g ss fib rs, inding m t r a s pp i d to h rs, so that eac or the fibersis coated with a binding agent when in the as; semblageof glassfibers Composing the glass fiber mat or pad. The binding agent is` of a; type that can be subseqnently activated or reactivated to causea bonding between thefibers at, their points o f juncture. A com; mon. ind ng. en s for hispu pose. is. a, ph nol. fo ma d hy e. resin..

How ver,. otherf n ing; gen s su h s he. v rious vinylresins or styrene or silicon:1' esins, orasphaltiocorn: pounds, can be used as the binding agent, depending entirely; uponthe class' of use to which the In tte fil` is pl ce Ih ndi g ge t,. be i h r a h tnl sat ing or. hertnop asti a er a e g n p ndin upon conditions of usage, parti cularly temperaturecone di ions.

T pr du e e. sho a s rp n. r sp n m ter a used in: this invention, continuous length or` staplelength glassfibers of theclass heretofore described. are brought intozan assemblageintheform of a mat or pad. In the normal procedure of producing glass fibers in matot pad form as collected upon an endless belt moving across the discharge opening of a Collecting hood, the glass fibers assume a generally common direction of their disposition relative` to one another in that` they tend toward` parallel. arrangement but due to felting effects of thefihersduring the course of their laying down on the endless eb on which they are collected, the as: sernbled matof glass fibers will have fibers disposed ngnlar ann n er nd ngul r o genera ire-. s tion of lay of the fibers, some of the fiber-s even being normal: to the direction of lay.

he m to ss eof g ss fib s ol e tedon he ndless. web. o elt, on t e ind r, pre e ab phenolforma-ldehyde, resin in an unpolymerized cpndition an witht ma e g of ny desir hickness, n, be, generally said that the glass fibers of, the mat are po -r sitioned horizontally, considering the belt or w.eb .be ing`fso disnosed during collection of the fibers.

The quantity of' glass fiber that is brought together. in alamina edassembhge s d p n upo he ens ty` of he. lass fibrouss. ma e alth t s o h p duced. 'It has. been e rm ne hat y o lin e ens ty o h glasstfibrons ate ia it pa s ien y. s pportin pressures ofa very broad range, butthat eachdensity of: he.n .ate a1; i l.,snpp, t p ssu es n y t i r a n. ranges resulting invarious degrees of compression of the lass fibt ns m teria Fo e mpl avg ss fib osussmat ialhaving a ensi y oi p n p ubic foott il isnppor p essur sot r m 0.1 p und p sq i h. at 1.5%, efie o to about,. p u ds p r squ r nc at. defiection. Glass fibrousmaterial havinga density of 20 pounds per cubic foot will resiliently support pressures from about 100 pounds per square inch at 15% deflection to about 1600 pounds per square inch at 65% deflection.

The assemblage of glass fibrous material is then placed between pressure plates to compress the assemblage of glass fibers to the desired density, as, for example from 1 pound to 20 pounds per cubic foot. Also, the determined density of the glass fibrous material is established when the material is at a desired thickness 'or height, dependent upon the dimensions desired in the finished product.

While the glass fibrous material is held to a desired density at a desired dimension between the pressure plates, the binding agent on the glass fibers is activated or reactivated to cause a bonding between the glass fibers at their various points of contact. Thus, when the pressure is released from the so-treated glass fibrous material it will retain the dimension at which it was compressed.

The so ,bonded glass fibrous material is then placed between other pressure plates which stress load the bonded glass fibrous material to compress it to an extent not less than thatat which it will be compressed when supporting the maximum load to be imposed on the material. A number' !of such cold working compressions or defiections are given to the material to stabilize the resilience factor of the material. This loading or stressing of the bonded glass fibrous material is occasioned in the same direction as that which will be occasioned upon the material when the supported load is applied.

The `efiect of the stress loading or cold working of the glass fibrous material is to eliminate the effect of any glass fibers in the material that tend to resist deflection of the material and to fracture those glass fibers that are improperly disposed in the material for cooperative resilient support of the load that is to be imposed on the material.

This stress loading of the glass fibrous material is eflEecfive to break or fracture the glass fibers that are improperly disposed in the glass fibrous material to the extent The stabilized product is now capable of producing repeat performance of spring loading with both a compression and extension of the material following substantially the same rate curve as shown by the typical load deflection curve of Figure 6. The amplitude of vibration absorption is regulated by the hysteresis loop shown on the load deflection curve. By varying the density of the material for a given load to be supported, and thereby varyingithe degree of compression or deflection of the material, various load deflection curves may be obtained with varying curve shapes on the hysteresis loop to secure the desired control over the amount of energy absorbed by the material in its defiection.

that they cannot fiex to the extent required by the deflection of the material under the load to be applied. Such fibers will fracture `or break and leave only the fibers that cooperate to support the load. This action of removing the fibers that tend to resist resilient action of the fibrous material results in stabilizing the resilience factor of the glass fibrous material.

-For example, in Figure 5 there is illustrated a chart showing the result of cold working or compression cycling of the bonded glass fibrous material. The material tested consisted of bonded glass fibrous material of a density of 6 pounds per cubic foot which was compressed .to 50% of its initial height and is to carry full load -at deflection. Normally cycling or cold working is carried 10% beyond The load defiection curve of Figure 6 is that of a stabir lized material of 6 pounds per cubic foot density under a maximum of deflection stabilized by cold working or stress loading ten times. The original free height of the material being 0.999 inch, with the new free height i after stress loading and stabilization being 0.994 inch.

The assemblage of the glass fibers coated with phenolformaldehyde resin is a combination of 5% to 25% phenol-formaldehyde and 95% to 75% glass fibers, with the preferred product containing 15 phenol-formaldehyde and 85% glass fibers. The' phenol-formaldehyde used as a binder is preferably of from 97% t0 40% by weight of phenol, and 3% to 60% by weight of formaldehyde.

the glass fibrous material is heated to a temperature of about 300 F., but which can be varied from about 250 to 450 F. There is a loss of about 8% by weight of the phenol product during curing. y The' material produced in accordance with the foregoing description can be used in the manufacture of body cushions or pads or like structures to support objects of irregular shape. Such a body cushion, or seat cushion, is illustrated in Figures 1 to 4. i

The seat cushion or spring unit of Figures 1 to 4 consists of a body unit 10 of glass fibers, preferably rocessed as hereinbefore described, but if desired the cold working or stressing of the body of glass fibers can be omitted in those instances where extreme act curacy of deflection of the glass fiber body is not re the maximum deflection of the material under maximum load to stabilize the resilience value of the material under full load conditions.

As represented in the chart, it will be seen that the initial compression of the material -to 50% of its initial height required -a load of about 16 pounds per square inch. After the first two compression cycles the load required to compress the material to 50% of its height reduced to about 8 pounds per square inch. It will thus be seen that the maximum degree of stabilization of the resilience factor is obtained in the initial loadings or compression stressings of the material.

Thereafter, up to the first ten cycles of stress loadings the pressure required for loading changes only a minor amount, the pressure loading being reduced from about 8 pounds per square inch to slightly over 7 pounds per square inch. At this point the glass fibrous material is sufliciently stabilized .that it can be said to be stabilized for all practical purposes. However, in the event for the need of extreme accuracy for the stabilization of the resilience factor, the material can be cycled an additional number of times until at about fifty cycles of stress loadings the product becomes fully stabilized for all practical purposes, even of extreme accuracies.

quired, such as in seat cushions, mattresses and the like. The glass fibers of the body 10 are disposed generally in acommon direction extending horizontally between the bottom face 11 and the upper face 12 of the cushion. Thus, the compression axis of the body 10 is in a vertical direction.

The body 10 has a plurality of slots 13 extending inwardly from the upper face 12 and partially through the body 10. As illustrated, these slots 13 are parallel -to one another. Similarly, slots 14 are placed in the body 10 from the face 12 which intersect the slots 13, thereby forming a plurality of individual body elements 15 that are completely free from one another to act independently of one another. Each of the body portions 15 form an individual spring element which acts independ- 'ently of the other spring elements. Thus when a body of irregular contour is placed upon the surface of the individual spring units 15, they will be defiected independently to support proportionately the weight that is applied on the cushion above the various spring elements.

By the construction of the cushion 10 as illustrated in the drawings, a highly flexible and resilient cushion is obtained which is capable of resiliently conforming to any irregular contour for support of the same. Glass fiber bodies constructed in the manner illustrated in` this invention are readily usable for mattresses, seat cushions and the like.

It willbe understood that the cushion body 10 can be provided with a suitable covering such as cloth, plastic or other material and the usual padding of sisal, cotton over the cushion in the usual way.

In curing the phenol-formaldehyde resin, for example,

Whenthe slots 13 and 14 are cut into the body` the smaller body portions thus have-a. resilience that is' different from the main unsevered body portion of the cushion because of their individual smaller areas involved. Thus, the uncut portion 10a of' the cushion 10 forms a firm but resilient support forthe elements 15 Which form individual springs for supporting a body. In Figure 7 the cushion is illustrated'in a modified position with the spring units 15 on the underside of; the cushion as it can be used inthis manner if desired.

While the cushion 10` of this inventionhas been illus trated as being formed from a body of: glass fibers of uniform density, yet it will be understood that thedensity of' glass fibers can be varied to obtain different values of' resilience in different areas of thecushion.

The slots 13 and 14 are preferably fabricatedintothe cushion 10 by the use of high speed cutting, tools, such asa saw, to sever the glass fibers* cleanly alongthe -;slots and thereby leave *the lay of the fibers undisturbedt Thus,` thevlay of the glass fibers in the individual springing 6.1.& ments 15 will be the same as in the' unseveredportion lila. of the cushion.

While there, is illustrated and described herein apreferred. form of the invention, yet it is understood that modifications that fall within the scope'of the appended claims are intended to be included herein.

We claim:

l. A glass fiber spring unit, comprising; a body unit of glass fibers bonded together at their points of juncture and resiliently compressible, said glassfibers constituting about 75 to 95% by weight of the spring unit, said body unit having a plurality of intersecting slots therein eX- tending partially through the body unit; subdividing the body portion containing the slots into a plurality of; separately, acting resiliently compressible spring units, said glass fibers being disposed generally in a plane' parallel to the upper and lower surfaces of saidbody unit.:

2. A glass fiber spring unit, comprising, a body unit of glass fibers bonded together at their points o tiuncture and resiliently compressible with the fibersdisposed generally in a .common direction through the body unit, said glass fibers constituting about 75 to 95 by weight of, the spring .unit, said, body unit having a plurality of intersecting slots, therein, extendi'ng. p rtially through. the body unit angular to the general direction of lay of the glass fibers thereby subdividing the body portion containing the slots into a plurality of separately acting resiliently compressible spring units, said glass fibers being disposed generally in a plane parallel to the upper and lower surfaces of said body unit.

3. A glass fiber spring unit, comprising, a body unit of glass fibers bonded together at their points of juncture and resiliently compressible, said glass fibers constituting about 75 to 95% by Weight of the spring unit, said body unit having a plurality of intersecting slots therein extending inwardly of the body unit from one face thereof and partially through the body unit subdividing the body portion containing the slots into a plurality of separately acting resiliently compressible spring units, said glass fibers being disposed generally in a plane parallel to the upper and lower surfaces of said body unit.

4. A glass fiber spring unit, comprising, a body unit of glass fibers bonded together at their points of juncture and resiliently compressible with the fibers disposed generally in a common direction through the body unit, said glass fibers constituting about 75 to 95% by Weight of the spring unit, said body unit having a plurality of intersecting slots therein extending inwardly of the body unit from one face thereof and partially through the body unit angular to the general direction of lay of the glass fibers thereby subdividing the body portion containing the slots into a plurality of separately acting resiliently compressible spring units, said glass fibers being disposed generally in a plane parallel to the upper and lower surfaces of said body unit.

6 5: Ax glass fiber: spring unit, comprising, a body' unit of glass fibers bonded together.- at their points* ofjuncture and'resiliently compressible with the fibers disposedgenerally in a common direction generally parallel between opposite faces of the body\ unit, said glassfibers con-. stituting about. 75 to by weight of the spring-unit, said body unit having a plurality of intersectingslots therein cX-tending inwardly ofvthebody unit; and partially through thesame and angular to the lay of the fibersin the body unit thereby subdividing the body portion con taining the slots into a plurality of' separately acting re silientlycompressible spring units, said glass fibers being disposed generally in a planeparallel to* the upper-and lower. surfaces of said body unit.

6. A glass fiber spring unit, comprising, a body unit. of glass .fibers bonded togetherat' their -pointsofjuncture and resiliently compressible with the: fibers disposed i generally in a common direction generally parallel between opposite, faces .of-` the hod-y unit, said body unit comprising by weight about 5 to; 25 phenol formaldehyde, resinand 75 to 95 glass fibers, saidbody'unit-having a plu-4 rality of intersecting. slots. therein extending inwardly of the body unit and partiallythroughthe same andnorrnal to the lay of the fibers in the bodyunit thereby subdivid-` ing the body. portion containing the slots into a plurality of separately acting resiliently compressible-spring-units, said glass fibers being disposed generally inna plane-parallel to the upper and lower surfaces. of said` body unit;

7*. A body cushion, comprising, a body-unit of glass fibers bonded` together at theirpoints of`junctureand resiliently compressible, said* body unit comprising by weight' about 5"'to 25% phenol formaldehyde resin: and 75' to 95 glass fibers, said'body unit' havinga plurality of' intersecting slots therein extendingpartially` through the body unit subdividing thebody portion containing the slots into a body of' separately acting resiliently: come pressible spring units, said' glass fibers beingdisposed generally ina plane parallel to the upper and lower surfaces of said body unit.

8'. A body. cushion, comprising, a body unit of glass; fibers bonded together at their points of' juncture and resiliently compressible with the fibers disposed generally in a common direction through the body unit; said body unit comprising by weight about 5 to 25% phenol formaldehyde resin and 75 to 95 glass fibers, said body unit having a plurality of intersecting slots therein extending partially through the body unit angular to the general direction of lay of the glass fibers thereby subdividing the body portion containing 'the slots into a plurality of separately acting resiliently compressible spring units, said glass fibers being disposed generally in a plane parallel to the upper and lower surfaces of said body unit.

9. A glass fiber spring unit, comprising, a body unit of glass fibers bonded together and forming a unit having a uniform density throughout the depth of the body and resiliently compressible, said body unit comprising by Weight about 5 to 25% phenol formaldehyde resin and 75 to 95 glass fibers, said body unit having a plurality of intersecting slots therein extending partially through the depth of the unit thereby establishing a plurality of separately acting small body portions with resilience different from that of the unslotted body portion, said bonded glass fibers forming a multiplicity of cantilever springs throughout said unit.

10. A body cushion, comprising, a body unit of glass fibers bonded together and forming a unit having a uniform density throughout the depth of the body and resiliently compressible, said body unit comprising by weight about 5 to 25 phenol formaldehyde resin and 75 to 95% glass fibers, said body unit having a plurality of intersecting slots therein extending partially through the depth of the unit thereby establishing a plurality of separately acting small body portions with resilience different from that of the unslotted body portion, said 7 bonded glass fibers forming a multiplicity of cantilever springs throughout said unit.

11. 'A method of producing a glass fiber spring unit including the .steps of, fabricating a body unit of glass fibers bonded together at their points of iuncture and resiliently compressible, said body unit comprising by weight about to 25% phenol formaldehyde resin and 75 'to 95% glass fibers, and fabricating into said body unit a plurality of slots extending partially through the body unit establishing thereby a plurality of separately acting springy portions.

12. A method of producing a glass fiber spring unit including the steps of, fabricating a body unit of glass fibers bonded together at their points of juncture and resiliently comprcssible, said body unit comprising by weight about 5 to 25% phenol formaldehyde resin and 75 to 95 glass fibers, and cutting into said body portion from one face thereof a plurality of slots extending partway into the body portion thereby producing a plurality of separately acting springy body portions Which are integral with the unsevered body portion.

13. A method of producing a glass fiber spring unit including the steps of, fabricating a body unit of glass fibers bonded together forming a body unit of uniform density and resiliently compressible, said body unit comprising by weight about 5 to 25% phenol formaldehyde resin and 75 to 95 glass fibers, and fabricating into the body unit fi'om one side thereof a plurality of slots extending partially through the body unit thereby producing 'separately acting body portions which are integral with the unslotted body portion.

14. A method of producing a glass fiber spring unit including the steps of, fabrica'ting a body unit of glass fibers bonded together* forming a body unit of uniform density and resiliently compressible with the lay of the glass fibers being generally in a common direction, said body unit comprising by weight about 5 to 25 phenol formaldehyde resin and 75 to 95% glass fibers, and fabricatiug into the body unit from one side thereof a plurality of slots extending partially through the body unit angular to the lay of the glass fibers thereby producing separately acting body portions which are integral with the unslotted body portion.

15. The method of producing a glass fiber cushioning crossing relationship thereby providing a plurality of separately acting springy glass fiber body portions integral with the unsevered body portion.

16. A body cushion composed of a body of glass fibers bonded together at their points of juncture and forming a multiplicity of cantilever springs for resilient action and slotted fro-m one face of the body transversely and longitudinally thereof and partially through the body thereby producing independently acting resilient glass fiber bodies on one side of the cushion, said glass fibers constituting about to by weight of said cushion and the remainder consisting of resinous bonding material.

17. A glass fiber spring unit, comprising, a compressi ble body unit of substantially uniform density of glass fibers bonded together and resiliently compressible, said body unit having a plurality of slots therein extending partially through the body unit subdividing the body portion containing the slots into a plurality of separately acting resiliently compressible spring units.

References Cited in the file of this patent a UNITED STATES PATENTS 2,002,399 Kaden May 21, 1935 2,325,026 Anway July 27, 1943 2,331,146 Slayter Oct. 5, 1943 2,338,839 Coss Jan. 11, 1944 2,371,788 Weeber Mar. 20, 1945 2,375,182 Anway May 8, 1945 2,489,242 Slayter et al. Nov. 22, 1949 2,785,739 McGregor et al Mar. 19, 1957 FOREIGN PATENTS V 403,249 Great Britain Dec. 21, 1933 476,678 Great Britain Dec. 8, 1937 

